Gant wrote:This Intelligencer article is fascinating. Via Digg.
THE MORE INFECTIOUS, THE BETTER?
The Best-Case Scenario For Coronavirus By David Wallace-Wells
nymag.com Coronavirus Health
The virus may be way more infectious than we think it is. If it is, it would mean we are closer to the end of the epidemic, and that the virus is much less deadly than we think.
Basically it's saying we don't know how many people have been infected. It could be we might get lucky and enter herd immunity more quickly than the initial information indicated. But that remains to be seen. Due to a lack of testing, the data isn't clear.
Also, the worldwide hunkering down for the good of all, has been more widespread and more effective than expected in curtailing the disease.
We need lots more testing. That's key.
Click the link to read.
https://nymag.com/intelligencer/2020/04/best-case-scenario-for-coronavirus.html?utm_medium=s1&utm_campaign=nym&utm_source=tw?utm_source=digg
I'm
extremely skeptical of any argument that we are anywhere close to having enough herd immunity to avoid hospitalization surges that would overwhelm our health care system, because it seems to conflict with obvious regional variations in COVID-19 incidence. Of course there are deficiencies in testing capacity, so testing capacity is driving reported case counts right now, which means that we can't trust the confirmed case count numbers and there is a huge amount of uncertainty about the true hospitalization rate and case fatality rate. But hospitalizations and deaths are not nearly as subject to testing capacity, and we see
enormous regional variation in COVID-19 hospitalizations and deaths. For example, California has fewer than 500 reported COVID-19 deaths, whereas New York has over 7000, so New York has over 10x as many deaths in spite of California having something like 5x as many residents. Let's make a really dumb rough estimate based on that that New York has about 50x the COVID-19 incidence as California. That would mean that even if New York has
100% incidence of COVID-19 (which isn't even close to true), that puts California at just 2%, which isn't going to do jack **** to protect Californians against a new outbreak if they stop their shutdown.
I'm not an epidemiologist, so take this with a huge grain of salt, but it's at least plausible to me that say NYC itself could have a high enough incidence of infection that there is some
modest level of protective herd immunity (although almost certainly nowhere close to a threshold where R<=1 if we resume normal economic activities). But I don't think we are seeing anything approaching herd immunity elsewhere. In fact, based on conversations with a friend who works at a hospital in rural New York where they have only seen a small number of COVID-19 patients so far, I don't even think we are seeing high enough incidence of infection in
New York state outside the NYC/Westchester/Nassau metro area to even start discussing what sort of protection we might get from herd immunity.
On a related note, Nate Silver mentioned this yesterday: there are two different and conflicting things people mean by "flattening the curve". R0 is how many people each infected person infects if nobody is immune, R is how many people each infected person infects when including immunity. At R<=1, the total number of infected people either stays the same or declines. One idea for "flattening the curve" involves allowing just as many total people to get infected, but spread it out over time so that we don't have a high peak and don't overwhelm hospital capacity before we reach herd immunity, which means we can end up in a situation where R0>1 but R<=1. That's what we have with a lot of other endemic diseases like the flu, which is why our hospital capacity doesn't get overwhelmed by influenza patients even though it is also very dangerous. The other idea involves using extreme measures to reduce R0 to <1, so that infection stops spreading even before we even reach a threshold of herd immunity, in order to shrink the infected population to a manageable number. The issue with the former strategy is that it results in a lot of hospitalizations and deaths, so even if the hospital system doesn't go over capacity, it still results in a lot of human tragedy. The issue with the latter strategy is that once you relax extreme measures, you still don't have herd immunity and end up with R>1 and a growing population of infected unless you figure out some way to reduce R0 to <=1 somehow (eg contact tracing and quarantine, continued physical distancing between people, wearing masks in public, etc).
I don't think the herd immunity strategy is realistic unless we are willing to allow a level of sickness and death that is far greater even than what we are seeing in New York. Exactly how many hundreds of thousands to millions of people are we OK with dying before we reach a herd immunity threshold? And even if we achieve herd immunity where we have just an endemic but manageable incidence of COVID-19 infection after that, are we going to just call that a job well done even though it will sometimes sweep through hospitals and nursing homes and kill off large percentages of our elderly and sick? It just doesn't seem like a thing most Americans would be willing to allow. So I doubt we're going to see true herd immunity until there's a vaccine to get us there, and as a result we're probably going to see a bunch of rolling shutdowns of social and economic activity as well as continued protective measures (physical distancing, contact tracing, masks, fewer social functions, etc) until we get an effective and safe vaccine.
